Preface

In the approximately 20 years since the 1988 publication of Volume 14, Forming and Forging, of the 9th Edition Metals Handbook series (renamed the ASM Handbook series in 1991), metalworking practice has seen a number of notable advances with regard to development of:

• New processes that include a number of novel techniques such as advanced roll forming methods, equal-channel angular extrusion, and incremental forging.

• Processes for new materials such as structural-intermetallic alloys and discontinuously-reinforced metal-matrix composites (MMCs) including dramatic approaches for the bulk forming of aluminide-based intermetallic materials and the utilization of commercial scale bulk forming for aluminum-alloy MMCs and, to a lesser extent, titanium-alloy MMCs.

• Improved microstructural control via specialized thermomechanical processing (TMP) of ferrous and nonferrous alloys with recent advances that include: TMP of ferrous alloys to produce carbide-free steels with bainitic microstructures and TMP of nickel-base superalloys to improve damage tolerance or creep resistance in service by techniques that produce a uniform intermediate grain size (ASTM ∼6) or a graded microstructure.

• Advanced tools for predicting microstructure evolution based on phenomenological models (predicting, for example, the evolution of recrystallized volume fraction and recrystallized grain size that evolve during hot deformation) and mechanistic models that incorporate deterministic and statistical aspects to varying degrees and seek to quantify the specific mechanism underlying microstructure changes.

• Advanced tools for predicting texture evolution based on models for the prediction of either deformation textures or recrystallization/transformation textures.

• Advanced modeling and optimization techniques using powerful and inexpensive computer hardware and software that have resulted in a revolution in the design of bulk-forming processes.

These developments are briefly described in the article “Introduction to Bulk-Forming Processes” with more detailed articles covering each of these new developments. This edition also includes a new section “Forging Design” with detailed forging examples from past work published in an ASM Forging Design Handbook.

In addition, content from the 1988 edition has been split into a two-volume set. This volume focuses on bulk-working operations that include primary operations, in which cast products or consolidated powder billets are worked into mill shapes (such as bar, plate, tube, sheet, wire), and secondary operations in which mill products are further formed into finished products by hot forging, cold forging, drawing, extrusion, etc. The companion Volume 14B focuses on sheet forming, which has several characteristics that distinguish it from bulk working; for example, sheet formability includes different criteria such as springback and the resistance of a sheet material to thinning. In addition, sheet-forming operations typically involve large changes in shape (e.g., cup forming from a flat blank) without a significant change in the sheet thickness, whereas bulk-forming operations typically involve large changes in cross-sectional area (e.g., round bar extrusion or flat rolling) and may be accompanied by large changes in shape (e.g., impression die forging or shape rolling).